What is reductio ad absurdum?

Reductio ad absurdum is to drive a premise to its logical extreme, even if the conclusions are false, and if they are false it shows the premise to be false. Meaningful reductio ad absurdum is an advanced form of deep learning, as opposed to purely formal mathematical emulations of reductio ad absurdum that are not transferable to identifying relevant empirical data. Since reductio ad absurdum is what allows falsifiability to rise above the level of mere trial and error, it is necessary for science to be science at all.

Some examples of reductio ad absurdum

The theory of a lumniferous aether was falsified by reasoning that if light was carried by a medium, the movement of the Earth would generate differences in the apparent speed of light in different directions. This allowed the measurement of the same speed of light in all directions (the Michelson-Morley experiment and its repetitions) to falsify the aether. If the "reasoning" had been "the speed of light is the same in all directions, therefore aether theory doesn't predict different speeds of light in different directions", aether would not have been falsified and we would not have known about special and general relativity. If you conflate the falseness of the conclusions with invalidity of the reasoning, thus failing to realize that the premise is false, you can't do science! Regardless of whether or not the conclusions are actually false, the consistency that underpins reductio ad absurdum is what makes science possible.

Adding reductio ad absurdum

If a prediction that follows logically from a H/T (hypothesis/theory) is not explicitly written in a H/T article, it can freely be added to it. You do not have to be the author of the article, others can add reductio ad absurdum too. For example, if a H/T article says that all vertebrates are stuck with hormones as the direct control of sexual characteristics in such a way that evolution cannot replace it with other controls, but has no written predictions about blood streams, any user can add the prediction "no vertebrates should have both ovum and sperm production connected to the same blood stream". And then any user (who may or may not be the one who added the reductio ad absurdum) can link to empirical data about deep sea anglerfish with their small males growing stuck on the bigger females and connecting their blood streams yet producing sperm and eggs respectively, thus falsifying the H/T.

Challenging reductio ad absurdum

Non sequitor and how to delete it

A reductio ad absurdum may be challenged and removed if it does not follow logically from the H/T (non sequitor). For example, claiming that "the theory of planetary migration predicts the existence of blue horses" (without explaining why) is a case of non sequitor. Claiming that a H/T makes a prediction merely because of polls or psychological "studies" claiming the viewpoints to be statistically correlated is non sequitor. One example of such non sequitor is to claim that "the H/T that fetuses can learn predicts the existence of immortal souls because the view that fetuses have minds is statistically most common in religious pro-life groups". It is important to note that the integration of all sapients in science, which is the goal of this wiki, makes it even more important to refute "statistical correlation" arguments that are often self-fulfilling prophecies that are to be debunked no matter what anyway. It is always wrong to assume that someone who adds or questions a reductio ad absurdum "behaves unethically" merely because he or she does not have an academic title in a particular "field" or because the criticism is expressed where people without such a title can read it (such as at this Media Wiki).

If you find a reductio ad absurdum that you think may be a case of non sequitor, please notify about it on that article's talk page.

Allegations of motives and toxic non sequitors

There are also cases of toxic non sequitor, such as allegations of ulterior motives. Such claims, as explained on the wiki's main page, are banned by the policy against assuming agendas. Their removal is high priority.

Completing an incomplete reductio ad absurdum instead of deleting it

However, it is sometimes possible that a reductio ad absurdum that skips one or more steps of explanation can be "fleshed out" into valid reductio ad absurdum. For example, simply saying that "the H/T that empathy is a specialized mechanism in the brain predicts that some people who are cruel to animals should be empathic to humans" is non sequitor, while "the H/T that empathy is a specialized brain mechanism that gradually evolved by extension from closer kin to more distant kin, by primitive functions being evolutionarily necessary but not sufficient conditions for more derived functions, predict that some people who are cruel to more distant kin should be empathic to closer kin, including some cruel to strangers yet empathic to their family and some cruel to animals yet empathic to all humans" is valid reductio ad absurdum. See also can a diagnosis be a falsifiable H/T?

It is also possible to include conditions under which a reductio ad absurdum does not apply without removing falsifiability, but only if there is a reason in the H/T itself for those particular conditions but not other conditions suspending the prediction.